Organic Waste Recycling

208 Organic waste recycling: technology and management

Figure 4.23 Ethanol production process

Some limitations of ethanol production from biomass raw materials include:

• Competition for land to be used for food crops and energy crops. As
  several economically developing countries are not self sufficient in
  food production, too much cultivation of these biomass raw
  materials for ethanol production may lead to reduced land area
  available for cultivation of food crops for human and animal
  consumption.


• Land degradation and loss of soil fertility. Because they are high
  yield crops, if without proper soil management, land areas used for
  growing these biomass raw materials may lose soil fertility in a
  short period of time.

4.7.2 Ethanol production process

The production of ethanol from biomass raw materials normally involves;
storage and preparation of the raw materials, fermentation, distillation and
drying and ethanol storage. A brief description of the above process is given
below.

Carbohydrates

Dextrins

Simple sugars (C 6 H 12 O 6 )

C 2 H 5 OH

Alpha- amylase enzyme

(Long chain water soluble sugars)

Yeast(Saccharomyces cerevisae)

Gluco-amylase enzyme